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Tuned-frequency energy sources can be used to selectively deliver energy to a tumor for improved therapeutic outcomes or to address difficult-to-treat diseases. For example, some tuned-frequency energy sources include focused ultrasound, gamma ray knives, and proton beams. Each energy source has advantages and disadvantages.
Proton therapy utilizes externally generated beams of protons to destroy cancer cells through an ionizing, DNA-damaging mechanism. Proton therapy can be applied clinically to a range of cancers, such as in the uveal tract, cervical spine, pituitary gland, skull, brain stem, and spinal cord. Proton therapy has a well-defined range, or penetration depth, in tissue. Much of the energy transfer from the protons takes place at the end of the linear trajectory of the protons, represented by a Bragg peak. By modulating the energy of incoming protons, the biologically effective dose may be conformed to different depths, spatially localizing the dose to the tumor. This total conformed radiation dose can be represented by the Spread-Out Bragg Peak (SOBP).
Gamma therapy such as a gamma knife therapy or brachytherapy utilizes gamma rays to destroy cancer cells. Gamma knife therapy includes directing external gamma rays at a tumor. The gamma rays can be generated by a radioactive cobalt source. Brachytherapy includes implanting radioactive seeds next to a tumor. The radioactive material in the seeds emits gamma rays as the material decays. The gamma radiation causes cell death by damaging cell DNA. Gamma radiation varies in efficacy and mode because of different energetic qualities, biological absorption, and other factors.
Improved radioisotope energy sources can offer new treatment modalities that are likely to improve cost effectiveness, economics, therapeutic outcome, and may enable treatment of currently intractable disease.